This work has been completed and has been submitted to Anesthesiology for consideration for publication. The abstract of the paper is as follows: Because of evidence suggesting that volatile anesthetics interfere with platelet aggregation in vitro, we investigated platelet function in patients exposed to general anesthesia during brief surgical procedures. In twelve patients undergoing elective operations, blood was sampled before anesthesia, after induction but prior to surgery, during surgery, and post-operatively. Platelet aggregation by ADP, ephinephrine, and collagen was similar during each sampling period in all but two subjects. During brief exposure to general anesthetics, there appears to be no clinically important inhibition of platelet function.